Chalkiness Characters and Scanning Electron Microscope Observation of Rice Grain Endosperm of Japonica Varieties in Southern Henan

Chalkiness characters affect not only the grain appearance,milling,eating and cooking qualities but also the grain nutritional quality in rice,thus it is one of the most important traits in rice. It is very important for us to investigate the relation of the chalkiness formation and the development of endosperm structure and starch granule of different rice varieties. Here,we have investigated the chalkiness characters such as chalkiness rate,chalkiness degree and chalkiness area in 15 japonica rice varieties from southern Henan. Furthermore,the endosperm structure and starch granules of rice grain were also observed with scanning electron microscope. The results showed that the 15 japonica varieties have a significantly linear relationship between the chalkiness rate and chalkiness degree. Among the varieties,the biggest difference is the chalkiness rate,the second is the chalkiness area,and the last is the chalkiness degree. Moreover,there is a certain correlation between the distribution of starch granules,the arrangement of endosperm cells and the occurrence of grain chalkiness in the different rice varieties. For the same variety,the starch granules of chalky and non-chalky grains have obvious difference,while the starch granules from the transparent part of chalky rice and non-chalky rice do not have significant difference. The results would provide useful references for the improvement of grain quality in rice.

Effect of Different Sowing Dates in South Henan 's Rice-growing Areas on the Growth and Yield of Ratoon Rice

In order to determine the optimal sowing date of ratoon rice in South Henan's rice-growing areas,this paper performs a comparative analysis of rice growth process,seedling quality and yield of first season rice and ratoon rice under different sowing date treatments. The results show that under climatic conditions( 2014),by using dry seedling cultivation in a small plastic shed,the growth of seedling sown on February21 was affected,while the sowing treatments from March 1 to April 11 can breed normal seedlings,and in this period,the maturity period of first season rice was delayed with prolonged sowing date,and ratoon rice yield declined with prolonged sowing date( total production of rice sown on 11 March reaching a peak). Thus,it is considered that the optimal sowing date of ratoon rice in South Henan's rice-growing areas is mid-March.

A Method for Detection of Main Metabolites in Aromatic Rice Seeds

[ Objective] A method was developed for the analysis of main metabolites in aromatic rice seeds by gas chromatography-mass spectrometry （GC-MS）. [ Method] The main metabolites in seeds of 9 different aromatic rice varieties were compared and analyzed with two methods. Method 1 ： the compound was extracted by the mixture of anhydrous ethanol and methylene chloride （ WV = 1：1 ） at 60 ℃ for 3 h in water bath; the extract was isolated and detected by gas chromatography-mass spectrometry using HP-5 capillary column with scan monitoring mode. Method 2： the main metabolites in aromatic rice seeds were detected using headspaee solid phase micro-extraction and gas chromatography mass spectrometry （GC-MS）. [ Result ] Fifteen types of common metabolites were found in 9 different aromatic rice varieties. Method 1 was more effective than method 2 in detecting the main metabolites in aromatic rice seeds. [ Conclusion] This study provides an important reference for clarifying the metabolic pathway of main metabolites in aromatic rice and lays the foundation for further rice breeding.

Genetic Analysis and Improvement Strategies of Protein Content in Rice Seeds

Enhancing the nutritional quality of food crops is a way to improve human nutrition and health. Grain protein content （ GPC ） is an important nutritional quality trait for rice and many other crops. Therefore, it will be very significant to increase GPC and improve rice quality. This paper mainly reviewed the genetic studies GPC in rice, mapping and cloning of QTLs and genes associated with GPC. However, little is known about the molecular mechanism and gene function related to GPC in rice. Thus, here we put forward the genetic strategy by gene pyramiding or molecular marker assisted selection to improve GPC and nutritional quality in rice. This review could provide important information for genetic improvement of grain nutritional quality of rice.

Expression and Regulation of Plant Amino Acid Transporters and Their Application in Crop Genetic Improvement

Amino acid transporters( AATs) play an important role in transport process of various amino acids,which are indispensable in plant growth and development,while many putative AATs have been identified and the complete genomic sequences of the important plants have already been completed by splicing and assembling. There is still little knowledge about the expression,regulation and various biological functions of AATs in plants,including the major food crops. This study mainly reviewed the expression,regulation and various biological functions of AATs in plants,and the application of AATs in crop genetic improvement was also prospected. Thus,this review will provide important information for genetic improvement of staple food crops in plants.

Selection of Thickness of High Density Polyethylene Film for Mulching in Paddy Rice

In water deficit area, judicious use of water is essential for increasing area under crop production with limited water supply. Film Mulching has been advocated as an effective means for conserving soil moisture in rice production. The effects of high density polyethylene (HDPE) film on increasing rice production, controlling weeds and residue amount of plastic were studied under five treatments, including 5, 10, 15 and 20 μm thickness as well as bare cultivation (CK). The results indicated that the HDPE film mulching mode had significant effects on weed control, soil temperature, soil moisture, photosynthetic rate, seedling biomass, yield and residues of plastic film. Combined with economic effect, it showed that the HDPE film of 10 μm is the best option for rice production.

Expression Regulation of Starch and Storage Protein Synthesis Related Genes in Rice Grains

Starch and the storage proteins are the main nutritious substances in crop grains,and their composition and content in grains play a decisive role in the grain quality of rice and other staple food crops.This review has mainly summarized the new advances in the expression regulation of starch and storage protein synthesis related genes in rice grains.Moreover,the challenges of the starch and storage protein synthesis substances in rice genetic improvement were also discussed.This review will provide important information for genetic improvement of grain quality in rice and,potentially,other staple cereals.

Vacuolar phosphate transporters account for variation in phosphate accumulation in Astragalus sinicus cultivars

Astragalus sinicus is a commonly used legume green manure that fixes atmospheric N2 and accumulates mineral nutrients and organic substances that are beneficial to soils and subsequent crops.However,little is known about genotypic variation in,and molecular mechanisms of,Pi(phosphate)uptake and storage in A.sinicus.We recorded the morphological responses of six A.sinicus cultivars from four regions of China to external Pi application and measured their Pi accumulation.We identified full-length transcripts of Pi-signaling and Pi-homeostasis regulators by sequencing and measured the expression level of these genes by qRT-PCR.The major components in Pi signaling and Pi homeostasis were largely conserved between A.sinicus and the model species rice and Arabidopsis.Different A.sinicus varieties responded differently to low-phosphorus(P)stress,and their Pi accumulation was positively correlated with the expression of vacuolar Pi influx gene(SYG1/PHO81/XPR1-MAJOR FACILITATOR SUPERFAMILY(SPX-MFS)-TYPE PROTEIN)AsSPXMFS2 and negatively correlated with the expression of the vacuolar Pi efflux gene(VACUOLAR Pi EFFLUX TRANSPORTER)AsVPE1.We identified key Pi-signaling and Pihomeostasis regulators in A.sinicus.The expression of vacuolar Pi transporter genes could be used as an index to select A.sinicus accessions with high Pi accumulation.